For diesel engines in idle, controlling the injection quantity of diesel fuel individually by combustion chamber, i.e., individually by cylinder for a diesel engine, in such a way that all combustion chambers provide an essentially equal torque contribution to a total torque of the diesel engine, is known.
For pollutant reduction, in diesel engines of this type, a part of the exhaust gas is regularly recirculated into the combustion chambers. It has been shown that with increasing service life of the diesel engine, the pollutant emission, in particular the nitrogen oxide emission, rises. If an increase of the pollutant emission is established, an extensive technical diagnosis is necessary to find out the causes, to thus be able to maintain legal pollutant emission limiting values. In addition, an increased pollutant emission of diesel engines results in an increased environmental stress.
It has also been shown that the pollutant emissions differ for various diesel engines of the same manufacture. Maintaining pollutant emission limiting values is an important quality criterion. To be able to ensure the maintenance of the pollutant emission limiting values for all diesel engines from a manufacturing plant, strict manufacturing tolerances are to be maintained, which requires technically complex quality control.